Automatic vacuum bagging devices of the prior art are generally used to preserve hygroscopic powdered, granulated, or crushed material, perishable in air or moisture, under the best conditions and in the smallest volume.
Up to now, different types of vacuum packaging have been used, which were generally organized around an articulate chute carrying the bag and controlled by a set of jacks. The bag, hooked to this chute, was placed in a vacuum during the bagging operation by means of an external pump, connected to openings provided on the walls of the chute.
This arrangement served, on the one hand, to evacuate the air contained in the bag and, on the other hand, to facilitate the operation of compaction obtained by means of a vibrator located on the floor of the shaping compactor, on which the bag rested.
All of these arrangements were characterized by a reservoir of materials to be packaged, provided in its lower part with a flexible or rigid sleeve that could be closed if necessary. The packaging bag was connected to the sleeve by means of a rigid or articulated chute, whose opening was controlled by a set of two hammers driven by jacks. The upper part of the bag fixed to the chute was protected from all pollution by means of sealing strips connected to each other in order to flatten the top of the bag against the outer walls of the chute.
After the operations of filling and deaeration obtained by means of an attached pumping circuit, the product was compacted by means of a vibrator placed under the platform carrying the bag. The bag, the vibrator, and the platform were placed within a rigid box installed inside two shelves mounted on a slide rail, so as to open in the manner of a jaw, and closing on the lower part of the chute.
On the upper part of the box were found two parallel bars controlled by a set of jacks and springs, which could rip the upper part of the bag located under the chute at two different pressures, depending on whether a vacuum packaging was being carried out or a simple deaeration of powdered materials capable of closing a closing-off of the circuits.
During certain bagging operations, the shaping box closed on the bag at the level of the chute and was made tight by means of a gasket placed permanently between the two shelves. The box was then placed under reduced pressure by means of another external pumping arrangement, in order to accelerate the operation of filling of the bag, compaction of the product contained, and its shaping, thus increasing the packaging speed.
Other arrangements used more rudimentary bagging techniques, carried out by means of a turntable intended to distribute the materials to be packaged into different bags in a continuous manner by means of a chute and a hopper.
All of these types of arrangements showed numerous advantages, in particular:
minimum space occupied PA1 moderate cost of the bagging installation PA1 good quality of packaging. PA1 a tricky or even difficult working, requiring a particular adaptation for each product, PA1 a rapid fouling of the circuit of deaeration and flow of the materials to be packaged, PA1 discontinuous operation, PA1 a low yield with a limiting speed, PA1 in the case of the use of the arrangement with a rotary turntable, it was difficult to carry out a deaeration of the contents of the bag and its compaction simultaneously, PA1 air pollution was also created when powdered materials generating an aerosol were used. PA1 an optimal yield PA1 easy working PA1 high durability for a reliable operation PA1 a perfect tightness with respect to the surrounding atmosphere PA1 a low cost/profit ratio.
On the other hand, this technology showed numerous disadvantages, particularly during use of the articulated chute: